Chain-driven ratchet wrench



Nov. 21, 195o J. D. ST'RQBELL 2,530,553

CHAIN-DRIVEN RATCI-IET WRENCH Filed Oct. 2, 1947 INVENTOR JOHN D. STROBELL Md/umu? ATTORNEYS Patented Nov. 21, 1950 UNITED STATES PATENT OFFICE CHAIN-DRIVEN RATCHET WRENCH John D. Strobell, New Haven, Conn. Application October 2, 1947, Serial No. 777,523

3 Ciaims. 1

This invention relates to ratchet tools, especially ratchet wrenches, and has for its object the provision of certain improvements in tools of this character. My invention is particularly concerned with improvements in ratchet wrenches for bolts and nuts and provides a means for the rapid turning thereof to save time, as in the assembling and disassembling of machines.

The usual ratchet wrench is operated by short strokes requiring quite some time in threading or running a loose nut down to, or from, its tight position. My invention provides a means in the handle of the wrench and operable in combination with the ratchet for turning the nut or bolt engaging means (turning head) of the wrench without turning the handle. The wrench of my invention comprises a turning head with a sprocket and an endless roller type chain in the handle of the wrench operable on the sprocket, and a hand-operating means with a ratchet engaging the chain to drive the chain and turning head continuously in one direction by reciprocable strokes of the hand-operating means. The chain and ratchet serve the dual function of turning the head and the nut comparatively rapidly while it is loose and as a ratchet for the nal tight setting of the nut.

One of the features of my wrench is that the turning head, which is always operated in one direction by the chain, is preferably symmetrically constructed so that a nut may be run on or off (turned either direction) merely by turning over the wrench. The turning head preferably has an integral sprocket wheel for the chain and engaging holes or lugs extending axially in opposite directions from the sprocket to engage connectors, bars, sockets and the like for connecting with nuts or bolts.

These and other objects of the invention will be better understood after considering the following discussion taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a plan view, with parts broken away, of a socket wrench embodying my invention;

Fig. 2 is a view along line 2-2 of Fig. 1;

Fig. 3 is a sectional view of a modified form of turning head, and

Fig. 4 is an enlarged View of a modified ratchet mechanism of the invention. y

The ratchet wrench illustrated in Figs. land 2 comprises a hollow casing or handle I formed of two similar anged pieces 2 and 3 which may be made as by stamping or machining and held together by screws 4, 5 and `I, or other means. Near one end, hole 'I is provided to form bear- 2 ings for the mounting therein ofthe turning head 8 having an integral sprocket 9. of the invention, the turning head has a square lateral hole IB for the insertion therein of .a connecting bar Il, as shown in broken lines, which may be removable and used for engaging with standard sockets such as the common automotive type sockets.

Near the opposite end of the casing a freely rotatable guide roller I2 is mounted on the shaft or trunnion I3. While I prefer to use a sprocket as shown which is a companion for sprocket 9, I may use any suitable` form of pulley. The endless roller type chain Ii is mounted inside the casing and over the sprockets, the center distance of the latter being such as to eliminate slack from the chain. The inside narrow dimension of the space in the casing is slightly more than the overall width of the chain and the inside width of the casing is slightly more than the overall diameter of the chain on the sprockets. Both sprockets are preferably of the same pitch diameter. The hat wide sidesof the casing are provided with longitudinal slots I5 and IS on a plane embracing the axial centers of the sprockets.

A freely movable block or shuttle 20 is mounted within the casing and between the loops of the chain which has lateral extensions 2l and 22 slidable in the slots I5 and I6. The main body portion of the shuttle is so proportioned that it will slide freely in the space between the loops of the chain and inside the casing without interference. The projections 2l and 22 not only guide the shuttle on the center line of the two sprockets but provide a convenient means for the attachment of a gripping member such as the sleeve 23 attached to the extensions 2i and 22 by the screws 2li. Any suitable hand-operating means may be attached to these extensions. In the body of they shuttle 253 are provided two square or rectangular recesses 25 and 26 facing opposite sides in which the compression springs 21 and 23 are inserted. These springs bear against and urge outwardly the square or rectangular pawlg 3E) and SI `so that their beveled ends S2 and 33 enter between the rollers of the chain. The bevels of the pawls may be fiat or curved and are faced in opposite directions.

The use of the wrench will be described in connection with the screwing of a nut onto a stud. After the nut has been started on the stud, the socket (not shown) which is attached to the connector I I in the usual manner is placed over the nut, the handle end 3A of the casing is held in one hand, and the sleeve 23 is grasped in In this form` the other hand and recprocated back and forth. As the shuttle is moved toward sprocket I2, the pawl 3l engages a roller in the right hand side of the chain (Fig. l) and causes the chain to translate, turning the two sprockets and consequently the nut. The position of the bevel 32 of pawl 30 is such as to allow the rollers of the left side of the chain to pass by. The nut Will be rotated in a clockwise direction.

When the shuttle reaches the end of the slots l5 and I6, its direction is reversed and on the return stroke pawl 3 engages a roller in the left hand Side of the chain while pawl 3l allows the chain to pass by. It will be noted that the translation of the chain is always in the same direction, regardless of the direction of travel of the shuttle. Therefore, by reciprocating the shuttle the nut will be run quickly on the thread of the stud.

When the nut can no longer be turned in this manner, either because the thread becomes tight or the nut comes to a bearing, a ratchet action of the wrench is available without the need of making adjustments. It is simply necessary to oscillate the wrench through an arc. The action is as follows: With sprocket 9 stationary and the casing turning in a clockwise direction, the relative motion between the casing and the sprocket tends to cause the chain to run onto the sprocket and as pawl 3| is engaged with a roller of the chain the shuttle will tend to be moved toward the sprocket. However, pawl 30 is also engaged with the chain and as this side of the chain is moving in the opposite direction from that of the other side of the chain it will tend to move the shuttle away from sprocket 9. The result is that the casing, sprocket, chain and shuttle become a locked assembly preventing relative movement between the casing and sprocket and clockwise motion of the casing applies a clockwise torque to the nut. Turning the casing in a counterclockwise direction reverses the relative motion between thev chain and casing, both pawls allowing the chain to pass freely by the shuttle and thus no torque is applied to the nut. The shuttle may be at any point in its stroke during the ratcheting action and it will remain in that position as thel action of the two sides of the chain on it are equal and in opposite directions.

Fig'. 3 illustrates a modified form of turning head construction. The turning head all is mounted in the holes 4l, as previously described, and has av unitary member comprising a sprocket 42 similar to sprocket 9 and connector lugs 43 and 44 which are square in cross-sectional area and adaptable to direct engagement with the usual sockets. It is to be understood, of course, that the turning head may comprise any suitable connecting means or shape for engaging tools or articles to beV rotated.

Fig. 4 illustrates a modied form of shuttle 59 which reduces the amount of lost motion in the type of shuttle illustrated in Figs. 1 and 2 in which the minimum ratchet angle will be 360 divided by the number of teeth in the sprocket 9. By using two pawls 5|, 52 and 5?, 54 on each side of the shuttle as in Fig. 4,.spaced so that the distance between their engaging beveled surfaces is equal to one or more times the chain pitch plus one-half Q f the chain pitch, the ratchet angle will be reduced by one-half.

In the action of the wrench as described above andr referred to in Fig. 1, the torque is applied in a clockwise direction. If the wrench is turned over so that the socket isapplied to. the opposite side from that shown in Fig. 1, its action is reversed so that if applied to a nut the resulting torque action will be counterclockwise to loosen the nut and manipulation of the shuttle will turn the nut in the same direction to run the nut off the stud.

The various parts of the wrench are relatively simple and can be made cheaply. In operation, the wrench eiects a material saving in the time required to run nuts on or off bolts or studs. The wrench will operate as a ratchet wrench and requires no adjustment to change the direction of action.

I claim:

l. An improved socket wrench which comprises a handle, a turning head mounted on the handle. a sprocket on said head, an endless chain engaging the sprocket and mounted in the handle, a hand operable shuttle mounted in the handle, at least two pawls in the shuttle urged outwardly in opposite directions by springs, each pawl having a beveled surface facing oppositely from the bevel surface of the other pawl, said pawls being arranged to be inserted between the rollers of the chain by action of the springs, said shuttle being reciprocable to run the chain continuously in one direction by alternate driving engagement of the pawls with links of the chain, and engaging means on both sides of the turning head to run a nut in both directions by turning the wrench over.

2. An improved ratchet wrench which comprises a hollow casing which serves as a handle, a turning head mounted in one end portion of the casing, said turning head being provided with a tool engaging means, a sprocket-on the turning head, an endless roller type chain engaging the sprocket and mounted inside the casing, a xed roller means mounted inside the casing and in a position opposite the turning head for securing the other end of the chain in the casing, guide slots in the casing, a shuttle in the casing and between the loops of the chain, spring pressed pawls in the shuttle extending in opposite directions from each other for engaging rollers of the chain, guide members on the shuttle slidable in the slots for directing the movement of the shuttle along a plane embracing the axis of the turning head, and means for reciprocating the shuttle by hand to drive the chain and turning head continuouslyv in one direction, said Vpawls serving as ordinary ratchet pawls for operating the turning head by oscillating the handle.

3,'A ratchet wrench according to claim 2 which comprisesl a turning head which has similar engaging means'on opposite sides, whereby on turning the wrench over a nut may be run in the opposite direction.

JOHN D. STROBELL.

REFERENCES CITED The following references are of record in the le .of this patent:

UNITED STATES PATENTS Number Name Date 668,387 Neale Feb. 19, 1901 1,263,435 `Klingbiel Apr. 23 1918 1,611,790 Starr Deo. 21, 1926 2,009,409 Parker July 30, 19435 2,288,217 Trautman June 30, 1942 FOREIGN PATENTS Number Country Date 336.933 Great Britain srv-. July 23, `192,9 

